This study tests if a special treatment called **VNS Therapy** is safe and works well for people with **Treatment-Resistant Depression** (TRD). VNS stands for **Vagus Nerve Stimulation**, a therapy that uses a small device to send electrical signals to the brain. People in the study are divided into two groups: one gets the VNS therapy, and the other does not. The main part of the study lasts for 12 months, but participants may continue in a longer study for up to 5 years.

**Key Points:**

• Participants must have had depression for at least 2 years or 4 episodes and failed at least 4 treatments.
• The initial study period is 12 months, with a potential to continue for 5 years.
• Participants should not have other serious mental health disorders or be on investigational treatments.

This study is important to see if VNS Therapy can help people who haven't found relief from other treatments. If you qualify, you may get the chance to try a new kind of therapy that might help with your depression symptoms.